Speaking to Barbara Walters in an upcoming 20/20 interview, Alley said: "I know John with all my heart and soul; he's not gay.

"I think in some weird way, in Hollywood, if someone gets big enough and famous enough, and they're not out doing drugs and they're not womanising, what do you say about them?"

Alley also described Travolta as the "greatest love of [her] life", explaining that she fell for him while she was married to Parker Stevenson.

"It took everything I had inside, outside, whatever, to not run off and marry John and be with John for the rest of my life," she said. "I feel like when you marry someone, you're supposed to work hard at it and you're supposed to make it work."